1. Field of the Invention
The present invention relates to a method for assessing the number and type of flaws on a substrate while distinguishing between flaws such as a scratch or scratches and those of particles, based on the coordinate data for the positions of all of the detected flaws. The present invention is particularly useful when a flaw detection device detects a scratch or scratches made by a pincette or the like on a substrate, such as a semiconductor wafer.
2. Description of the Related Art
Flaws existing in a semiconductor manufacturing apparatus can reduce the production yield. In order to avoid a reduction of production yield, it is necessary to remove flaws attached to the inner walls of the semiconductor manufacturing apparatus. The removal of flaws is started when the number of flaws existing on a semiconductor wafer reaches a predetermined value. To determine the number, the number of detected flaws such as particles existing on a semiconductor wafer is counted.
When a scratch made by a pincette or the like exists on a semiconductor wafer, a flaw detection device detects the scratch as a plurality of flaws. In other words, a flaw detection device detects both particles and a scratch or scratches as flaws.
Therefore, flaw removal may not have to begin simply because the number of flaws detected by a flaw detection device exceeds a predetermined value. However, it is necessary to begin flaw removal when the value obtained by subtracting the number of flaws from a scratch from the number of all flaws detected by the flaw detection device exceeds a predetermined value. Therefore, the number of flaws from a scratch on a semiconductor wafer must be determined. Herein, "a scratch" is defined as flaws from a scratch or scratches and/or the like on a semiconductor wafer made by, for example, a pincette or the like, that are detected as flaws by a flaw detection device. Herein, "particles and the like" are referred to as simply "particles".